The application of mass spectrometry to the study of biological molecules has revolutionized many aspects of biomedical research. A group of eighteen NIH-supported research groups located at UMDNJ-Robert Wood Johnson Medical School and Rutgers, the State University of New Jersey Piscataway Campus) are requesting a ThermoFinnigan Deca XP Plus mass spectrometer equipped with a nanospray interface and capillary HPLC system to complement our existing shared MALDI-TOF mass spectrometry resource. The user group members propose to use this instrument to perform biomedically relevant descriptive and differential proteomics studies, de novo protein sequencing, and protein identification, identification of posttranslational modifications, cross-linking analysis, as well as physical and structural biology studies. Many members of the User Group currently employ mass spectrometry as an integral part of their research. However, most currently must send samples to other facilities for analysis, creating a barrier to the timely accomplishment of research goals. In addition, some of the users require direct access to a LC/MS/MS system for protein analysis and there is no available resource on campus. All of the users would therefore benefit enormously from having the requested instrument. This would result in significant increases in productivity. More importantly, this resource will allow the investigators to expand their research in new directions, and to begin new projects that could not have previously been undertaken.